Nadh synergism of microsomal aniline metabolism in the presence of enhancing agents

NADH, which normally has no effect upon the NADPH-dependent metabolism of aniline by the microsomal fraction, exerted a synergistic effect in the presence of various enhancing agents, including acetone. Acetone enhanced the rate of aniline metabolism but inhibited the NADPH-dependent reduction of cytochrome P-450, showing that this is not the rate-limiting step in the metabolism of aniline. It is suggested, however, that acetone might facilitate the transfer of the second electron to cytochrome P-450 and that this may normally be the rate limiting step in the metabolism of aniline. The increase in metabolism did not, of itself, appear to be responsible for the synergistic effect exhibited by NADH in the presence of enhancing agents.